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Citizen science is a relatively new phenomenon in the Czech Republic and currently a general overview of existing citizen science projects is not available. This presents the challenge to uncover the ‘hidden’ citizen science landscapes. The main objective of this paper is to explore the (public) representation of citizen science (CS) projects and to describe their heterogeneity. The study aims to answer the question of what type of projects in the Czech Republic meet the definition of citizen science. Based on a specific methodological data-base search approach, we compiled a set of CS projects (N = 73). During the classification process, two general citizen science categories were identified. The first group (N = 46) consists of “pure” CS projects with a prevalence towards the natural sciences, principally ornithology, and thus corresponding to general European trends. Citizens usually participate in such research in the form of data collection and basic interpretation, and a high level of cooperation between academia and NGOs was detected. The second group of “potential” CS projects (N = 27) entails various forms of public participation in general, frequently coordinated by NGOs. Based on these results, we discuss the position of citizen science in the Czech Republic, including socially-oriented citizen science. Further research is strongly encouraged to achieve a more in-depth insight into this social phenomenon.

Temperate forests are undergoing significant transformations due to the influence of climate change, including varying responses of different tree species to increasing temperature and drought severity. To comprehensively understand the full range of growth responses, representative datasets spanning extensive site and climatic gradients are essential. This study utilizes tree‐ring data from 550 sites from the temperate forests of Czechia to assess growth trends of six dominant Central European tree species (European beech, Norway spruce, Scots pine, silver fir, sessile and pedunculate oak) over 1990–2014. By modeling mean growth series for each species and site, and employing principal component analysis, we identified the predominant growth trends. Over the study period, linear growth trends were evident across most sites (56% increasing, 32% decreasing, and 10% neutral). The proportion of sites with stationary positive trends increased from low toward high elevations, whereas the opposite was true for the stationary negative trends. Notably, within the middle range of their distribution (between 500 and 700 m a.s.l.), Norway spruce and European beech exhibited a mix of positive and negative growth trends. While Scots pine growth trends showed no clear elevation‐based pattern, silver fir and oaks displayed consistent positive growth trends regardless of site elevation, indicating resilience to the ongoing warming. We demonstrate divergent growth trajectories across space and among species. These findings are particularly important as recent warming has triggered a gradual shift in the elevation range of optimal growth conditions for most tree species and has also led to a decoupling of growth trends between lowlands and mountain areas. As a result, further future shifts in the elevation range and changes in species diversity of European temperate forests can be expected. [ABSTRACT FROM AUTHOR]

The Arctic, one of the most sensitive components of the Earth's climate system, experienced pronounced climatic fluctuations during the Late Holocene. In order to obtain a detailed record of past environmental and climatic variability, sedimentary cores from two interconnected infilled depositional basins in the Kobbefjord area, southwestern Greenland, were retrieved and subjected to a multi‐proxy investigation. The absolute chronostratigraphy was established through radiocarbon (14C) and short‐lived radioisotope (210Pb, 137Cs) dating. We also analysed magnetic susceptibility, grain size, X‐ray fluorescence element composition, total content of carbon, nitrogen and sulphur, biogenic silica and diatom assemblages. The palaeoenvironmental reconstruction presented from the upper basin records ~800 years of sedimentation in a former shallow Arctic lake/pond that was modulated by catchment processes and regional hydroclimate. The record is dominated by alternating periods of increased organic and clastic deposition, suggesting warmer/drier and colder/wetter climate, respectively. Comparison of our records with other proxy‐based lacustrine, marine and glacier records and instrumental measurements from Greenland and the North Atlantic reveals common climatic trends, consistent with the inferred North Atlantic Oscillation pattern. Periods at ~800–600, ~320–220 and ~140–30 cal. a BP correspond to the main cold phases. The earliest climatic deterioration coincides with the demise of the nearby Norse Western Settlement. The most recent cold period represents the culmination of the Little Ice Age with the maximum Holocene advances of Greenland glaciers. Ameliorated conditions predominated at ~550–320 and ~220–140 cal. a BP. The evolution of both water bodies is concluded by transition into oligotrophic peat bogs after complete infilling of the basins at ~30 cal. a BP. Despite differences in proxy signals between the coring sites, this study endorses the usefulness of shallow lake/pond sediments from infilled basins for environmental reconstructions, as long as local depositional processes do not mask the external driving factors. [ABSTRACT FROM AUTHOR]

The Arctic is one of the most sensitive areas worldwide with respect to climate changes, and recent climate change impacts are evident throughout Arctic ecosystems. In order to put current and projected changes in a palaeoclimatic context, exact information of past conditions and therefore detailed knowledge of proxy archives are crucial. Here, we investigated wood anatomical and other growth-related records of the long-lived and widespread Arctic tundra shrub Juniperus communis L. Annual ring-widths and cell anatomical parameters of 20 individuals from south-west Greenland were measured to test for age-related trends in the proxy time series and to correlate them with past climatic conditions. We documented a clear age trend in the investigated growth parameters (ring-widths, conduit-lumen areas, and cell wall thicknesses), which indicates the need for detrending the time series prior to possible climate correlation analyses and climate or environmental reconstructions. Prostrate growth forms of J. communis do not exhibit the general trend of an exponential widening of the conduit-lumen areas during ontogeny, as has been observed for many tree species, but their conduit lumens stop to increase in size at some point. This is possibly caused by a combination of extreme climate and physiological adaptations, which result in a prostrate growth form. Of the tested growth parameters, only detrended cell wall thickness showed stable correlations with summer temperature and the summer standardized precipitation evapotranspiration index (SPEI). The other growth parameters did not pass cross-calibration verification analyses, although for ring-widths we found the strongest climate correlations. Despite the fact that the ecophysiological processes behind our observations (i.e. reduced cell wall thickness combined with wider rings under dry conditions in the vegetation season) yet are not fully understood, we recognize the potential of J. communis for climate reconstructions. To our knowledge, this is the first demonstration of using cell anatomical parameter of J. communis shrubs as palaeoclimatological proxy for the Arctic. [ABSTRACT FROM AUTHOR]

The article presents a paper that determined the rate of Arctic juniper primary growth in southwest Greenland. Topics discussed include studies of tundra shrubs having become vital parts of Arctic activities, their applications varying from fields including population ecology to carbon storage and permafrost thaw.